Question

When `3.36 x 10^4` liters of oxygen reacts with propane, how many molecules of water are produced?

Answer 1

Perhaps you're referring to the combustion of propane,

`CH_3CH_2CH_3(l) + 5O_2(g) to 3CO_2(g) + 4H_2O(g)`

Generally, for gases at STP, we can assume that `1"mol" approx 22.4"L"` since other conditions aren't given.

Hence,

`3.36*10^4"L" * "mol"/(22.4"L") * (4H_2O)/(5O_2) * (6.02*10^23"molecules")/"mol" approx 7.22*10^26`

molecules of water vapor are produced stoichiometrically.